B5 1.8t Timing Belt Failure... FML

[ActiveMonkey]

So yesterday evening I'm cruising down the freeway and the engine just stalls. Wtf?! I pull over and look around in the engine and then I see it. The moment I pulled the timing belt cover I see a good number of teeth are missing from the belt. AAA got the car home and the tear down will began. I sadly couldn't find my head bolt tool so the rest will have to wait until I can go find another head bolt tool. I do have my 2003 A4 parts car from which I can go harvest an AMB head. Then install the new head, gaskets, and a new timing belt followed closely by crossing some finger for the compression test.

Last night I did pull the plugs and send a borescope in to see the damage. It looks similar, maybe not as bad as pictured in the VW Vortex thread.
http://forums.vwvortex.com/showthrea...ed-piston-tops

Questions:

1 - Does anyone know of any reason why the AMB wont work in place of an AWM head?

2 - If/when the valves hit the piston, if the valves scratched or very slightly marred the piston head from the impact would I have to replace the piston head?

3 - Any advise or is there anything I am not thinking of?

[seanf86]

if its just small marks you can dress them down with a roloc disc or similar so you don't get hot spots on the piston head. The AMB head is identical, just check it for cracks, CCT/cams/yadda yadda are all identical. You will want to reuse your AWM valve cover as the 2003 will have a small port in the back for the different AMB pcv system.

[ActiveMonkey]

any recommendation on what final grit to use on the piston head after all marks are gone?

[Turbo_B5]

how old was the belt?

[ActiveMonkey]

i was told it was changed at 80K (now at 119k) but apparently the dude was full of shit.

[xdewaynex]

That sucks. When I got my A4, I changed the timing belt after 3 months of owning it. Got the car at roughly 140k miles not knowing if the belt had ever been changed, but I wanted that added security. Just replaced the belt again this week with the addition of the IE's manual tensioner setup.

[Turbo_B5]

ouch. no reciept=change that fcuker. Good luck getting this sorted out.

wtf how did that doublepost happen??

[ActiveMonkey]

1/3 of the teeth on the belt stripped off. 12 valves are bent, piston heads have small marks from the valves. I cleaned the enormus amount of carbon build up and marks off the piston heads with roloc discs and im now pulling the AMB head off the parts car.

The #10 polydrive socked did NOT fit my head bolts. Really is a major inconvenience and nobody is open on Sundays.

[vrmm]

You try tapping that poly drive on? Or for that matter hammering. You're aware of the difference between oem and aftermarket bolts I assume? You can use one in place of the other. At least.. I always have.

[ActiveMonkey]

You try tapping that poly drive on? Or for that matter hammering. You're aware of the difference between oem and aftermarket bolts I assume? You can use one in place of the other. At least.. I always have.

I did not try tapping or hammering the poly drive socket on. These are OEM head bolts and it is an after-market # 10 polydrive (T52) 1/2" drive socket. I just assumed that the point I purchase was a piece of shit and didn't work well. I was able to get them off with an elongated T50 torx.

What is the difference between OEM and aftermarket head bolts?

[walky_talky20]

Firstly, I feel your pain.

When you redo, I would suggest the latest OEM timing belt tensioner setup for the AWM. It is a spring-loaded automatic tensioner, without hydraulic dampener. This design is borrowed from the newer 2.0T engines. Often referred to as the "Litens tensioner" setup as Litens is the manufacturer of the spring-loaded pulley. Do note that the 2.0T parts will not work, as there is a belt offset difference among other things. You have to get the Litens stuff specifically for retrofit to the 1.8T. Also note that officially only the "late" AWM engine is meant to receive this update, however an "early" AWM can be updated without issue. The only requirement is to obtain the "late" AWM/AMB tensioner stud.

For whatever reason, ECS and other vendors still don't appear to have a kit made up for this latest tensioner system update. There are a couple options:

- INA Kit from Blauparts. $185

- Piece together your own kit:
> "119F" Timing belt (Continental) or (Gates Racing...because Racecar)
> Litens tensioner: 06A109243A
> New small roller to use with your existing hydro tensioner body.

The Litens tensioner through genuine Audi is pricey. I purchased a "Febi" version for about $60 and it was stamped "Litens", but did not bear the Audi rings. It was good stuff and I would recommend. Some other discussion of details here: http://www.audizine.com/forum/showth...1#post11143881

[ActiveMonkey]

**UPDATE**

Pictures Failed Belt



Damage



After initial clean/buff. After this photo was taken I did clean the block surface and perform additional cleaning/buffing...



Head Gasket in Place and Pistons adjusted to TDC



AWM head on LEFT - AMB head on RIGHT (already adjusted to TDC)

[ActiveMonkey]

You try tapping that poly drive on? Or for that matter hammering.

I cringed and tapped the O'Riley VW/Audi Head Bolt tool into the head bolts on the AMB head and it worked. I'll be damned if it was not a PITA to pull the head bolts off the tool though.

[ActiveMonkey]

Bad news is that everything is back together but it idles like shit. In setting the timing and reading through a ton of threads i put the #1 cylinder at TDC when head was off and marked the gear. For the cams i used the 2 arrows on the back of the cams which point to the notches. In my case, the left arrow was the the left of the notch and the right arrow to the right of the notch. My best guess is that i am off 1 tooth but i am unsure how.

Any advice on how to correct?

[ActiveMonkey]

Never should've doubted for one second. The reason it idled like crap was the quarter inch bung just below the throttle body.

Runs smooth as hell now.

[andyrew]

Quick turnaround on your fix! Good job! I used some 80 grit by hand to round the edges of some knicks and used a tiny file on others. You should be fine if you dont push the engine.

[Believer]

Quick turnaround on your fix! Good job! I used some 80 grit by hand to round the edges of some knicks and used a tiny file on others. You should be fine if you dont push the engine.

Would you be able to elaborate on this thought a bit? If he were to push the engine, what wouldn't be fine? I am asking because I am using pistons in my motor that have almost identical marks, from when a timing belt popped on the motor they came from. I am definitely pushing my motor and i'm wondering if I may be getting hot spots causing issues I can't seem to track down.

[ActiveMonkey]

Quick turnaround on your fix! Good job! I used some 80 grit by hand to round the edges of some knicks and used a tiny file on others. You should be fine if you dont push the engine.

After doing this, pulling the whole motor wasn't much more. I suppose if it does break i'll just pull the motor and put in a different AWM and it would also be a good time to install a new clutch so....

Fun ain't free, but it's worth it.

[xdewaynex]

Good turn around, and nice to hear its all back together.

[ActiveMonkey]

Thanks, to my surprise the engine now runs smoother than before and my oil temp is also a tad lower. I'm still a tad concerned with longevity so while this thing lives I'm going to start hunting for a new AWM motor at the pick n pull.